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Editor’s note: This article is the first installment of a new Groundswell series on carbon footprints. We’re aiming to dispel myths about daily energy use, and share real, lasting, affordable (and often money-saving!) tips to making a change in your energy lifestyle. Stay tuned for future editions, and let us know if you have questions on carbon footprints in the comments!

If you were asked right now how big your carbon footprint is, what would you say?

“Calculate my carbon footprint? Gross—I don’t want to feel bad about myself.”

It’s easy to be cynical about carbon footprints—it’s a buzzword used (and sometimes overused!) by the environmental movement. But what are they really? And what’s the point in calculating yours?

Very simply, your carbon footprint is the amount of carbon dioxide and methane that the day to day actions of your lifestyle produces. A more accurate term would be your greenhouse gas footprint should really include the amount of carbon dioxide, methane, and nitrous oxide your actions add to the atmosphere. These gases make up the greenhouse gases that lead to global warming, which causes starving polar bears and the not too distant annihilation of every good beach.

We all have a carbon footprint. The trick is how big it is.

Why calculate your carbon footprint?

It’s no secret that the land of the free likes to go big. The average carbon footprint for a US household is 5 times the world’s average.

A lot of that is because many of us live in places built for driving from point a to point B—and when we take trips, lots of us plan to fly.  The other big carbon suck is housing: the materials you use, the energy you burn, and the waste you produce. Next comes food: red meat, dairy, and seafood products top the list there.

There are a number of reasons to know where you stand in terms of greenhouse gas emissions. I think the most useful part of a carbon footprint calculator is that you see all the surprising factors that contribute to the amount of energy you consume—because once you know what uses a lot of energy, you’ll know better how to reduce your footprint, and how to save yourself some cash, too.

It can be overwhelming to consider the amount of damage human activity causes the environment. But the flip side of that is that there are always actions we can take to have a positive impact. A household carbon footprint calculator shows you small ways to change your input. Knowing your carbon footprint can let you plan on ways to focus on offsetting your carbon footprint—switching to a carbon neutral form of energy like wind or solar—with a goal of being carbon neutral.

Knowing your carbon footprint enables you to set goals and take action from there. Plan to lower your carbon footprint by 10 or 25 percent, then identify ways to meet your goal. Could you drive less? If you live in a walkable neighborhood and/or near public transportation, this is a great bet. Can you change your average thermostat setting by a few degrees? Go meatless one or two nights a week?

Calculating your carbon footprint on an annual or even quarterly basis can help you engage with how you’re consuming resources and make adjustments, big and small, that help keep us sustainable.

Here’s How to Calculate Your Own Footprint

Want to take that first step? Here’s two ways to do it quickly:

1. Use an online carbon footprint calculator

A good place to start if you’re curious about your carbon footprint is a carbon footprint calculator. (Sounds easy enough, no?) There are a lot of carbon footprint calculators on the web, but they’re not all created equally. The broader the assessment, the less likely you are going to be able to figure out places where you can tweak things.

Before you choose one, see what they base their calculations on. I would recommend a research based model to make sure that you’re getting reliable numbers. A few calculators that follow academic research are the one at UC Berkeley (I mean, c’mon, if Berkeley doesn’t have some smart environmentalists, we’re all screwed), and another is at CarbonStory.

A lot of these carbon calculators will offer specific recommendations to reduce your footprint—whether it’s driving less, adjusting your diet, or reducing waste, there’s a combination of factors (bad and good) at work.

2. Calculate it on your own

DIY can be more accurate, though it will require more effort on your part. Basically it’s a two parter: figure out your inputs, and then figure out how much carbon that means (via a formula). Here are the main categories you need to figure out your footprint:

i. Housing:

For housing, you need to factor in energy as well as water and waste.

Energy includes electricity, which is based on the sources of electricity that you use, and fuel—so there will be variations depending on your heating and cooling processes and other factors.

Waste emits a great deal of methane, but water production can be very carbon intensive as well.

ii. Travel:

There are specific formulas for different forms of travel. You figure out your weekly average mileages for driving, flying, and taking different forms of public transportation.

iii. Food: 

Different types of food have different environmental costs, so taking stock of your average consumption will show you what has the most impact environmentally. Eat a lot of meat or dairy? Your footprint will be a lot bigger than a vegetarian’s in this respect.

iv. Products:

This is a big category! What are the goods you buy in a month? This includes anything from toiletries and paper goods to clothing, medical supplies, or sports equipment.

Determining this number may require looking at monthly purchases, then breaking them into a weekly average.

v. Services: 

From health care to communications, each service you use has its own network of buildings, transportation, and hard goods that carry an associated carbon footprint.

Determine your inputs for each separate portion and then multiply by the emissions for each aspect using formulas for each items emissions. Add up the results to find out your score.

Finding out how your carbon footprint breaks down is definitely the most accurate way to figure out your impact and target areas to change it, but it is time consuming. If the more general carbon footprint calculators are easier for you to start thinking about, then do that—you can always dig deeper once you hit your first greenhouse gas goal!

Whether you use a calculator, do he calculations on your own, or choose an app, measuring your carbon footprint can help you figure out where you’re already helping the planet, and where you can work towards doing it better.

Emily Rabbitt is a freelance and fiction writer in the Washington, D.C. area. She is a Massachusetts native, iced coffee enthusiast, and marathon runner, and tries to be a good citizen of the planet. Follow her on Twitter: @rabbitterun.